Printing processes utilize different technologies to transfer written content to various distribution media. Organizations using varying printing processes include modest-volume quick printers, book and financial publishers, newspaper companies, forms companies, all sizes of commercial printers (for advertising etc.), and, publication printers (for magazines and periodicals). These types of organizations may use an offset printing process whereby information is transferred from some original layout form to an intermediate aluminum or polyester plate material which is then “hung” on a standard printing press to enable multiple identical replication of that information on paper or some similar print media.
The offset process has conventionally been performed by optically creating a polyester film which contains the information, optically transferring the information from the film to a plate material by use of a light transfer or contact to a light-sensitive chemical emulsion which is bonded to the plate. The developed plate is then hung on a press in alignment, one plate for each color separation desired. The plates rotate along with the press cylinder and alternately come in contact with ink rollers and then an intermediate transfer blanket. The ink, which is accepted by the transfer blanket, then transfers the information to the paper during rotational contact.
Recently the development of computer-to-plate systems and high-quality digital printing systems has provided alternative printing options. A summary of such options, and the advantages of variable information enabled by the digital printing technology is described, for example, in the “FreeFlow Variable Information Workflow,” white paper prepared by Interquest, Ltd. For Xerox Corporation (Copyright 2004 Xerox Corp.), which is hereby incorporated by reference in its entirety.
Regardless of whether an intermediate film is used to produce printing plates or whether they are imaged directly from computerized equipment, the information to produce the printing plates or color separations may be stored in sets of orthographic files that have been prepared with multiple layers of overlaid variable data. A set of such files may be processed in an offset printing workflow where different layers of color can be applied by separate offset printing plates to facilitate multiple versions of a printable image. The variable data for address one is overlaid with the data for address two, etc. The address placement is controlled by applying the appropriate color in the production process. The pages are done one at a time or imposed in sections.
After printing, there is a laborious manual process required to sort and collate the pages (or groups of pages) into the proper collection for the production of a version of one document of a multi-versioned set. Digital printing eliminates this need for manual sorting and collating.
In reference now to FIG. 9, an image file or set (600), containing the information needed to print a single image is shown. This file is broken down into different color planes, which correspond to the offset printing plates (610). Each plate contains a partial image containing only the parts of the image that correspond to a particular color of ink to be used. Each of the offset printing plates (610) is then used in sequence to print (620) multiple copies of the partial image it contains. Each partial image is sent back to the printer, in proper sequence, to have the next partial image contained in the next plate superimposed by the printer onto the image. The sequencing operation is shown by the arrows (630) that depict printed output being cycled back to the printer to have the next part of the image printed. Different degrees of manual intervention may be required to perform the proper sequencing of the print medium back to the printer for the next layer of color, depending on the complexity of the print job.
A known solution to the manual labor requirement inherent in offset printing is digital printing where the entire image, with all its colors, is printed at once. However, digital print quality has been traditionally perceived to be inferior to conventional offset printing by many consumers such as commercial advertisers, publishers and others. One cause of this perceived difference in quality may be that digital printing conventionally produces images using dry toner, while offset printing uses ink. Although the barrier between the two printing methods has been overcome there are particular applications in which one or both printing methods are appropriately employed. As will be described in more detail below, on such application is a large, variable-data, multi-version document (such as a workbook or teacher's guide, having information that may vary from state to state based on the varying curriculum). Documents of this sort may be economically produced in large runs using offset printing techniques. However, for purposes of proof or short runs, it may be advantageous to produce the documents using a digital printing system. In this situation, the printer would prefer to maintain the image information in a common format, so as to avoid having to reorder or edit the files used to compose the document for printing.
Because of these technological advances and the expectation of further advances to come, it is desirable to increase the use of digital printing technology, to eliminate the need for unnecessary labor, and to increase the productivity of the publishing process. Therefore, it is desirable to provide a digital system and method for compiling images for printing that can leverage the flexibility of digital technology while enabling existing conventional image information for offset printing orders to be utilized more efficiently.
According to aspects illustrated herein, there is provided a method for compiling images for a limited run of a document, comprising: selecting a set of computer readable images to be compiled; queuing the computer readable images into a memory; combining the computer readable images into a single first document image, said image including a version key and a color plane associated with said version key; sending said first document image to a digital front end processing system, said system using the version key to create a second image wherein said second image, in response to the version key, lacks at least one color plane of said first image; and sending said second image for rendering.
According to aspects illustrated herein, there is also provided a method for compiling images for printing comprising: using a computer to select a set of computer readable partial images to be compiled; using a computer to queue a set of computer readable partial images to be compiled; using a computer to combine a set of computer readable partial images into a single first image in portable data format comprising a version key and a color plane associated with said version key; sending said first image to a digital front end processing system; sending version key selection information to a digital front end processing system; using a selected version key to create a second image in portable data format that causes a raster image processor to ignore selected color planes of said first image based on a selected version key; and sending said second image to a raster image processor.
According to further aspects herein there is provided a system for compiling images for printing comprising: a set of computer readable partial images to be compiled; a computer comprising a display means, a user input device, a central processing unit and a data storage means; a computer program product comprising a computer readable file containing instructions that, when executed by a computer cause the computer to combine a set of computer readable partial images into a single image in portable data format the single image comprising a version key and a color plane associated with said version key; a digital front end processing system comprising a display means, a user input device, a central processing unit and a data storage means; a raster image processor; and a communication means coupled to a computer, a digital front end and a raster image processor.